Removable drilling bit



Dec. 28, 1943. c. c. KOELN REMOVABLE DRILLING BIT Filed March 15. 1943INVENTOR (LC. KOELN BY 3/625 ATTORNEY Patented Dec. 28, 1943 REMOVABLEDRILLING BIT Carl C. Koeln, St. Louis, Mo., assignor of onethird toRichard L. Clark, St. Louis County, I

Application March 15, 1943, Serial No. 479,185

14 Claims.

My invention relates to well drilling apparatus and more particularly toa drilling bit therefor.

One of the objects of my invention is to produce an improved drillingbit and shaft attaching means for a rotary drilling apparatus so thatthe bit can be readily attached to and removed from the end of thedrilling shaft without the necessity of pulling the drilling shaft fromthe hole being drilled.

Another object of my invention is to so construct a removable drillingbit of the type referred to that certain cutters thereof will beautomatically adjusted to permit cutting of the central part of thebottom of the hole being drilled when the bit is caused to be attachedto the drilling shaft and automatically moved to a position permittingthe bit to slide on the drill ing shaft when it is to be removed.

Other objects of my invention will become apparent from the followingdescription taken in connection with the accompanying drawing in whichFigure l is a vertical sectional view of my improved drilling bitshowing it in operative position on the end of a drilling shaft, saidview also showing the device employed to lower' and lift the bit fromthe bottom of the hole; Figure 2 is a bottom view of the bit; Figures 3and 4 are sectional views taken on the lines 3-! and 4-4. respectively,of Figure 1; and Figure is a view of a different type of cutter whichcan be employed with the bit.

Referring to the drawing in detail, numeral l indicates the drilling bitbody. the peripheral surface of which .has an irregular contour as shownin Figure 2. This body is provided with acentral bore 2 which permits itto he slid over the usual hollow drilling shaft (not shown) of thedrilling apparatus. The lower end 01' this drilling shaft has secured toits end by threads, a specially constructed short hollow shaft 3 formingpart of the means for removably attaching the drilling bit body. Theshaft 3 is provided with a beveled end surface 4 and adjacent this endthe shaft is provided with an enlargement I having a portion of itssurface cut away to form right angle slots 8. The upper ends of theseslots have flared open ends with the side wall portions of adjacentslots converging to form apexes 7. The internal diameter of bore 2 isthe same as the external diameter or the enlargement 5 except at itsupper end 8 which is of decreased diameter in order to fit the portionof shaft 3 above the enlarged portion. Between portion 8 and the mainpart of bore 2 there is formed a shoulder 9 which is adapted to engagethe apexes 1 of the enlarged portion 5 on the lower end of the shaft.The angular slots 8 are shown as being four in number and cooperatingwith these slots are the inner ends of pins l0 carried by the bodyportion. These pins, together with the angular slots, form a bayonettype of Joint preventing any relative axial movement between the body ofthe bit and shaft 3 when the pins are positioned in the lateral legs ofthe slots. These pins also provide a driving connection between shortshaft 3 and the body of the bit so that the bit can turn with the shaftwhen the shaft rotates in the direction indicated by the arrow.

The lower end of the body of the drilling bit is provided with alternatelong and short radiallypositioned slots II and I2 extending in alongitudinal direction. In the short slots ii are positioned cutters l3in the form of blades which are held in the slots by screws M. The outeredges of these cutters extend slightly beyond the periphery of the bodymember and provide a cutting edge for forming the wall of the holewhereas the bottom edges of cutters I; provide the cutting means forcutting away the earth substance at the bottom of the hole adjacent theside wall thereof.

In each of the long slots l2, which extend completely through the wallof the body. is positioned a shdable cutter l5 provided on their upperends with converging edges l6 and i1. These edges are at right angles toeach other with each being at an angle of forty-five degrees with thevertical axis of the cutter. Each slot I2 is so cut in the body of thebit that the bottom wall it thereof is at a forty-five degree angle withthe axis of the bit body, thus providing a surface with which edge IS onthe cutter can engage. One surface of the cutter is provided with arecess l9 extending parallel with edge l6 and forming therewith a rib20. Received in said recess I9 is a portion of a tapered pin 2| which isfitted into a tapered hole 22 in the body at one side of slot l2. Thistapered hole is so constructed that when the tapered pin is positionedtherein the top of the pin surface wher it projects into the slot willbe parallel with the bottom wall I! of the slot. Thus when the cutter ispositioned in the slot, rib 20 will be confined between the pin and theend of the slot and thus hold the cutter from falling out of the slot.The construction also permits the cutter to slide radially outwardly anddownwardly in the slot or inwardly and up-' wardly in the slot with theedge 16 alway cooperating with the angular bottom wall it of the slot.In order that the cutter will b prevented from sliding out of the slotin a radial direction when the bit is out of the hole, the bit bodycarries a screw 23 (see Figure 4) for cooperation with the outer edge ofthe cutter.

When in its outermost position against the head of the screw, the cutterI will not project into the bore of the bit body. The outermost positionof the cutter, is shown in dotted line position in Figure 1. When inthis position it is apparent that the cutters I5 will not interfere withsliding the hit up and down on shaft 3 or the drilling shaft to which itis connected. When the cutter is in its innermost position,approximately half of its width wi l p ct into b re 2 of the bit body.The cutters are prevented from moving further into this here by theupper edge I1 abutting the beveled surface 4 on the bottom of shortshaft 3. When the bit is in operative position, the cutters I5 willassume their innermost positions and thus the lower edges of the cutterswill act as cutting means on the central portion of the bottom of thehole. Thus it is seen that all of the bottom of the hole will be actedupon by the cutters l3 and I5.

It is to be noted that because of the relationship of cutters IS withthe peripheral contour of the body member, the forward side edges ofcutters I3 are open to act on the side wall of the hole and the backs ofthe cutters are well supported by the body. The contour of the outersurface of the bit body provides space between the body and the wall ofthe hole for cuttings to be carried upward by fluid which is forceddownwardly through the drilling shaft and short shaft 3 into the bottomof the hole being drilled which is common practice during drilling,

When in operative position on the end of the drilling shaft, the bit isshown as in Figure 1. If it is desired to remove the bit, a special toolin the form of a retrieving ring is employed. This ring is shown inFigure 1 and comprises an annular element 24 carrying pivoted hooks 25.These hooks are adapted to cooperate with an annular ledge 26 providedon the upper end of the bit body. Each hook is cont-rolled by two cordsor cables 21 and 28 which also provide the means for raising the bitfrom the bottom of the well and also lowering it into the bottom .of thewell. When the bit is to be removed, the retrieving ring is lowered fromthe top of the well to where it engages the top of the body of the bit.The hooks can then be engaged with the ledge 26 by pulling on cords 28.

If the drilling shaft is now rotated in the direction opposite thatindicated by the arrow, there will be relative movement between theshort shaft I and the body member and pins ID will be moved intoalignment with the vertical portions of slots 6. If the retrieving ringis now pulled upwardly by cords 28, the body of the bit will also bepulled upwardly relatively to the short shaft 3. As the body of the bitmoves upwardly, cutters I5 will be forced outwardly and downwardly intheir slots by the wedging action between the angular edge I! and thebeveled surface on the bottom of shaft 3. When the cutters are movedsufficiently outwardly that no portion thereof extends into bore 2, thebit will be free to move upwardly and be removed from the hole bysliding it over the drilling shaft. When the bit reaches the top of thehole, it can be removed by merely detaching a joint of the drillingshaft and then a new bit substituted therefor. When the new hit is puton, the cutters I5 will be at their outermost positlons. thus freeingbore 2 of interference by the cutters. The hooks of the retrieving ringare now attached to the new bit and said bit lowered into the well bycords 28. When the bit reaches the short shaft 3 on the bottom of thedrilling shaft, pins I0 will find their way out into the flared verticalportions of slots 8. The shaft is now given a turn in the directionindicated by the arrow, thereby causing the pins to be positioned in thelateral portions of the slots to lock the bit against relativelongitudinal movement with respect to'the short shaft 3. When the bitand drilling shaft are now lowered into the bottom of the hole, cuttersI5 will engage the bottom of the hole and be forced upwardly andinwardly to their operative positions. The drilling operation can thenbe resumed as soon as the ring is brought back to the top of the hole.

It is to be noted from the above description of my improved drilling bitthat said bit can be removed and replaced by a new bit in a very shorttime without the necessity of pulling the entire drilling shaft whichtakes a long period of time even under the best conditions. This notonly saves time but also reduces labor cost as the bit can be changed byonly one person. The bit is so constructed that all parts of the bottomof the hole will be cut by the cutters when the bit is in operativeposition. The bit permits the usual drilling methods to be employedwhereby the cuttings from the cutters can be forced upwardly and out ofthe hole by liquid being forced down through the hollow drilling shaft.It is also to be particularly noted that the drilling bit is verysturdily constructed and that the cutters or blades are all fullysupported in the body of the bit. The slidable cutters I5 will bemaintained in their inner positions at all times as outward movement ofthe cutters is prevented by the angular edge I6 cooperating with theangular bottom surface of the slot. However, when the bit is to beremoved, these cutters I5 will readily slide to their outer positions inthe slots and free bore 2 so that the bit can be pulled up the drillingshaft.

The cutting portion of the cutter need not be the edge of a blade asother types of cutters can be employed with the bit, as, for example, arotary type. In Figure 5 there is disclosed a cutter IS, the upperportion of which is the same as the previously described cutter l5 andcapable of being mounted in the bit body in a like manner. The lowerportion of the cutter is provided with slots 29 of varying length inwhich are positioned wheels or discs of different diameters. Thesewheels or discs are rotatably mounted on a. shaft 3| so that when thebit is rotated, they will cut or grind the earth material. When thecutter I 5 is employed, similar cutters are substituted for the fixedcutters I3 so that the whole bottom of the hole will be worked upon.Preferably there will be two cutters capable or radial sliding movementand two fixed cutters. The wheels or discs of the different cuttersshould be spaced so that there will not be tracking."

Being aware of the possibility of modifications in the particularstructure herein described without departing from the fundamentalprinciple of my invention, I do not intend that its scope be limitedexcept as set forth by the appended claims.

Having fully described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

1. In drilling apparatus, a rotary drilling aeemso 3 shaft, a drillingbit body, means associated with the end of the drillingjshait and withthe bit body for attaching the body to the'lower end of the shaft so asto be rotated therewith while the 'lower end of the shaft remains"adlacent the bottom of the hole being drilled and for so detaching thebody that it will be free to be moved relatively axially of hole, acutter movably mounted on the body, and means for causing the cutter tobe moved to a position to operate on the bottom of the hole axiallybelow the end of the shaft when the body is attached to the lower end ofthe shaft.

2. In drilling apparatus, a. rotary, drilling shaft, a drilling bithaving abddy provided with a bore receiving the shaft, cooperating meanson the bit body and the lower end of the shaft for attaching the bit tothe shaft so as to rotate therewith and for detaching said bit by arelative rotation between it and the shaft so as to permit said bit tobe free to be moved relatively axially with respect to the shaft and outof the hole being drilled without the necessity of removing the shaftfrom said hole, movable cutters mounted on the bit, means'forautomatically moving the cutters into a part of the bore when the bit isattached to the shaft and the cutters are caused to engage the bottom ofthe hole. and means for moving the cutters out of the bore.

3. In drilling apparatus, a rotary drilling shaft, a drilling bit havinga body provided with a bore receiving the shaft, cooperating means onthe bit body and the lower end of the shaft for attaching thebit to theshaft so as to rotate therewith and for detaching said bit by a relativerotation between it and the shaft so as to permit said-bit to be free tobe moved relatively axially with respect to the shaft and out of thehole being drilled without the necessity of removing the shaft from saidhole, movable cutters mounted on the bit, means for automatically movingthe cutters into a part of the bore when the bit is attached to theshaft and the cutters are caused to engage the bottom of the hole, meansfor automatically moving the cutters out of the bore when the bit ismoved axially of the shaft, and means for moving the bit axially of theshaft.

4. In a drilling bit and drilling shaft construction permitting removalof the bit from a hole without removal of the shaft, a bit having a bodyprovided with a bore for receiving the shaft, detachable connectingmeans associated with the lower end of the shaft and with the bit, saidconnecting means being placed in a condition permitting axial movementof the bit relative to the shaft by a rotation of the shaft in adirection reverse to its direction of rotation employed in drilling, acutter mounted on the bit body for movement into and out of a portion ofthe bore, means for causing the cutter to be moved into the bore whenthe bit is attached to the shaft and thecutter is caused to engage thebottom of the hole, and means for moving the cutter out of the bore by amovement of the bit axially on the shaft.

5. In drilling apparatus, a rotary drilling shaft, a drilling bit havinga body provided with a bore for receiving the shaft, cutters mounted inthe body for radial sliding movement into and out of the bore.detachable connecti s means associated with the bit body and the end ofthe shaft permitting said body to be rotated the shaft to the top ofthe,

with the shaft in one direction of rotation thereof and to be soconditioned by a rotation of the shaft in the opposite direction andrelatively to the bit body as to permit the shaft to be free to be movedupwardly on the shaft and out of the hole, means for automaticallycausing the cutters to be so positioned as to extend into the bore ofthe body when the bit is operatively connected to the lower end of theshaft, and means for automatically moving the cutters radially out ofthe bore when the bit is moved upwardly relatively to the shaft.

6. In drilling apparatus, a rotary drilling shaft, a drilling bit havinga body provided with a bore for receiving the shaft, cutters mounted inthe body for radial sliding movement into and out of the bore,detachable connecting means associated with the bit body and the end ofthe shaft permitting said body to be rotated with the shaft in onedirection of rotation thereof and to be so conditioned by a rotation ofthe shaft in the opposite direction and relatively to the bit body as topermit the bit to be free to be moved upwardly on the shaft and out ofthe hole, means for automatically causing the cutters to be sopositioned as to exband into the bore of the body when the bit isoperatively connected to the lower end of the shaft, means forautomatically moving the cutters radially out of the bore when the bitis moved upwardly relatively to the shaft. and means for moving the bitover the shaft to the lower end thereof and for raising the bit whenpermitted by the detachable connecting means.

7. In drilling bit and drilling shalt constructlon permitting removal ofthe bit from a hole without removal of the shaft, a bit having a bodyprovided with a bore. for receiving the shaft, means on the bit andshaft preventing the bit from passing over the end of the shaft,interengaging means for connecting the bit to the shaft so as to berotated therewith in one direction, means for disengaging theinter-engaging means by a rotation of the shaft in the oppositedirection and relatively to the bit to thus free the bit for upwardaxial movement relative to the shaft, fixed cutters carried by the bodyof the bit and extending below the body between its outer surface andthe bore, other cutters mounted on the bit body for movement into andout of a portion of the bore, means for automatically causing themovable cutters to be moved into the bore when the bit is attached tothe shaft and the cutters are caused to engage the bottom of the hole,cooperating means on the lower end of the shaft and the cutters forautomatically moving the cutters out of the bore when the bit is movedaxially on the shaft, and means for moving the bit axially on the shaft.

8. In drilling bit and drilling shaft constructlon permitting removal ofthe bit from a hole without removal of the shaft, a bit having a bodyprovided with a bore for receiving the shaft, means on the bit and shaftpreventing the bit from passing over the lower end of the shaft,inter-engaging means for connecting the bit to the shaft so as to berotated therewith in one direction, means for disengaging theinter-engaging means by a rotation of the shaft in the oppositedirection and relatively to the hit to thus free the bit for upwardaxial movement relative to the shaft, radial slots through the body ofthe bit between its outer surface and the bore and open at the bottom ofthe body, the

closed ends or said slots bein: at an male to axle of the body, cuttermembers in the slots,

the bottom of slots being at cutters having cutters having an angularedge cooperating with the closed end surface and the bore and open atbore when shaft.

10. In drilling apparatus, a rotary drilling shaft, a drilling bithaving mounted on the member.

11. In a detachable bit for a drilling shaft, 9. bit body having a. borefor reception of the shaft, a radial slot in the body, a cutter having aportion received in the slot for radial movement. malntainin: the cutterportion in the slot and permittinl ite radial slidor a portion of theportion in a wedzins at.

12. In drilling apparatus, a rotary drilling shaft, a drilling bit bodyhaving a shaft receivto the lower end of the shaft.

13. In drilling apparatus, a rotary drilling body is positioned at thelowerend of the shaft.

14. In drilling apparatus, a, rotary bit body, and cooperatbit body, thecutter and the end of the shaft for positioning the cutter

